Karma-IV is a planet in the Karma System.

It is primarily a mercenary world, and is the home of Bartertown. The Karma Space Station is the home of Peepo's Pit.

From the Books: "Rick had to admire Karma Station as the Coronado braked with her ion drive. Compared to all the stations and habitats he’d seen in his home star system, it was tremendous. Three huge rings rotating around a stable central zero-gravity hub. Dozens of starships were parked around the station, many of them warships, with some freighters and a few ships of unknown utility. The planet looked a bit like Earth with huge oceans, white icecaps, brown/green land masses, and swirling cotton candy clouds. It was the most interesting place he’d seen since leaving home." - https://www.amazon.com/Winged-Hussars-Revelations-Cycle-Book-ebook/dp/B073WPM51K/Winged Hussars, p. 89.